Temp Alarm at Idle but water pump is working

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rorkin

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Started the boat today and ran at idle for about 10 min..
Suddenly the temp alarm came on..
Ran at higher speed and everything normal.
engine is pissing at idle but stream is a little weak.. I don't remember if that is abnormal..
Should I be replacing the pump now ??
 
the motor should be peeing strong even at idle....how old are the impellers? If you got 2 years on them, its time for a change....if they'er old, they may have taken a set and only giving good pressure at higher rpms
 
The poppet valve is a high pressure relief of the cooling water. I'm not sure how it looks on the 4 strokes but on the outside it's a bolted on plate with a 3/4" hose coming out of it. Behind that is a plunger with a spring attached to it that pushes aginst a rubber ring. As they get old they get a buld up of crud on the washer and don't seal well anymore. They're cheap and easy to do, but I'm betting on the water pump.
 
Yamaha

I have the exact same problem with one of my F225's. I had the water pumps done and pop its and still having a problem. My mechanic is suppose to get to it this week and see if he can find out what the problem is. He thinks it has to do with a spacer(shim) plate that he used on another engine that had the same problem. I will let you know if it works. He is suppose to get to it today or tomorrow.
 
BobP said:
Are you sure it is overheating?

When were pumps last done?
Click to expand...

Don't know bought the boat last year with 500 hours on it..

Dealer who had the boat said all reqd maintanance had been done but they could not get the service records.. Computer crash they said.
It was Norfolk Marine who is reputable so I belive them about the computer problem but really cant be sure.

We have jelly fish in numbers here so it is possible there was a
temporary reduction of water flow from one of them blocking the inlet.
Also I was idilig on the lift with intake in the water.. Possible it was drawing some pretty warm surface water.
I will keep an eye on it and change the pump etc at the end of the season. I will check on the poppett and see what develops from there
 
Can you touch the heads near the plugs and keep your hand there for several seconds? Both heads, not just one

Do this with motor off after alarm comes up.
 
Could the alarm have been for low oil pressure at idle. I'd check the dipstick if you haven't already. Let us know if adding some oil takes care of it.
 
Pez Vela said:
Could the alarm have been for low oil pressure at idle. I'd check the dipstick if you haven't already. Let us know if adding some oil takes care of it.
Click to expand...

Thanks but that is the first thing I thought of but I did look at the gague ant it was temp not oil.. Good guess :-)
 
BobP said:
Can you touch the heads near the plugs and keep your hand there for several seconds? Both heads, not just one

Do this with motor off after alarm comes up.
Click to expand...

Will do if it happins again.. I take it I should be able to put my hand there if it is at proper temperature. :-)
 
Yes.

But if your hand goes flying off and you cuse BobP, then it's overheating.

All alarm conditions should be verified for true prior to any corrective work plans.
 
Yamaha

The mechanic just changed the pumps again and all is working well. Don't know why there was a problem with the first new pumps but something caused the lowe idle overheat and now its fine with the new pumps. My mechanic did say he used non original Yamaha pumps first time and replaced with Yamaha original pumps now.
 
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